CORUNDUM AND DUMORTIERITE IN PEGMATITE 481 
faint blue to bright smalt-blue. Dumortierite could not be observed 
without the aid of the microscope. Bundles of radiating needles of 
sillimanite are occasionally met. Zircon occurs rarely. Secondary 
hematite is at times conspicuous. 
Pyrogenic character of the corundum.—Corundum is described by 
W. G. Miller? in granitoid rocks over wide stretches in the province 
of Ontario, Canada. It is present in syenite, in nephelite syenite, 
and in anorthosite. Professor A. C. Lawson has given the name 
plumasite to a dike rock made up of oligoclase and corundum from 
Plumas County, California.2 The granite of Nannie’s Mountain, 
near Yorkville, S. C., carries corundum.3 Morozewicz describes the 
occurrence of corundum in pegmatite in the Ural Mountains, inter- 
grown with orthoclase,+ and again as standing in the place of quartz 
in granite at Mikolskaja Ssopka, Ural Mountains, Siberia. He names 
this rock corundum syenite, and declares his belief that corundum 
occurs in these rocks as an original pyrogenic constituent. 
The remarkable occurrences of large amounts of corundum in 
close association with peridotite in North Carolina have been des- 
cribed by Dr. J. H. Pratt and Professor J. V. Lewis.5’ The view is 
held by these writers that much of the corundum in this association 
is an original constituent of the rock. The distribution of the corun- _ 
dum with reference to the peridotite masses is (1) peripheral, along 
the contact between the peridotite and gneiss; (2) in the peridotite 
masses in banded veins containing, besides corundum, the minerals 
chlorite, clinochlore, spinel, and enstatite; and (3) corundum occurring 
alone, inclosed by peridotite (dunite) at the Hayes Mine, Yancey 
1 W. G. Miller, “Economic Geology of Eastern Ontario,” Seventh Report, Ontario 
Bureau of Mines, 1897 (Toronto, 1898), p. 213. See also W. G. Miller, “The 
Corundum Bearing Rocks of Eastern Ontario, Canada,” American Geologist, Vol. 
XXIV (1899), p. 276. 
2 A. C. Lawson, “‘Plumasite, an Oligoclase Corundum Rock near Spanish Peak, 
Cal.,” Bulletin, Department of Geology, University of California, Vol. III (1903), 
pp. 219-29. 
3 J. H. Pratt and J. V. Lewis, North Carolina Geological Survey, Vol. I (1905), 
p- 222. 
4 J. Morozewicz, T. M. P. M. Vol. XVIII, p. 215, 1898. 
5 “Corundum and the Peridotites of Western North Carolina.”’ North Carolina 
Geological Survey, Vol. I (1905). 
